Vertex Pharmaceuticals announced that the US Food and Drug Administration (FDA) has granted Fast Track designation to VX-950, an experimental oral hepatitis C virus (HCV) protease inhibitor for the treatment of chronic HCV infection.

Fast Track designation indicates that FDA will speed up the development and expedite the review of promising experimental drugs for the treatment of a serious or life-threatening condition if it shows the potential to address an unmet medical need for such a condition.

VX-950 has the potential to shorten the duration of therapy compared to the standard of care (peginterferon alfa plus ribavirin), which may result in improved sustained virologic response (SVR) rates and a more favorable adverse event profile.

Vertex is currently conducting a clinical development program to assess whether VX-950 will address these unmet medical needs in HCV therapy.

VX-950 Clinical Status

Earlier in 2005, Vertex concluded a 14-day, Phase Ib study of VX-950 that showed a rapid and dramatic reduction in HCV RNA in HCV patients when VX-950 was administered as a single agent.

Overall in the Phase Ib study, adverse events observed in patients receiving VX-950 that were considered possibly related to the drug were mild, and generally similar in frequency to events in the placebo group. The most common adverse events reported in both placebo and VX-950 patients were headache, frequent urination and gastrointestinal symptoms.

Based on these encouraging Phase Ib clinical results, Vertex recently initiated two additional clinical studies with VX-950. In October 2005 in Europe, Vertex began a 20-patient Phase Ib study of VX-950 dosed in combination with pegylated interferon.

In December 2005, Vertex initiated in the United States the first Phase II study of VX-950, which will evaluate the safety, tolerability and pharmacodynamics of VX-950 when dosed with pegylated interferon and ribavirin.

Vertex expects to obtain results from both these Phase Ib and Phase II studies of VX-950 in early 2006. Vertex also expects to initiate multiple additional Phase II studies in the United States in 2006, including a three-month study in more than 200 treatment-naive patients.

Vertex Pharmaceuticals. FDA Grants Fast Track Designation to Vertex’s Investigational Oral Hepatitis C Virus Protease Inhibitor VX-950. Press Release. December 8, 2005.